HS1-Y397 phosphorylation correlates with LYN-Y396 activation in a subset of CLL patients. (A) Phosphorylation of the activatory residues on LYN and HS1 (2 upper panels) were evaluated by WB of representative primary CLL samples (patient numbers are as in supplemental Tables 1 and 2) with anti–phosphoLYN-tyrosine396 (α-P-LYN-Y396) and α-P-HS1-(Y397) antibodies, showing the concordant presence of the phosphorylation on both proteins. Total LYN and HS1 protein levels are shown (2 lower panels), as a control. (B) In the linear regression graph, OD values of LYN-Y396 phosphorylation (OD ratio between LYN-Y396 phosphorylation and the total LYN protein levels, y-axis) analyzed by densitometry of WB results from 40 primary CLL samples are represented and show significant direct correlation with the OD values of HS1-Y397 phosphorylation (OD ratio between HS1-Y397 phosphorylation and the total HS1 protein levels, x-axis). The numbers in the plot refer to the representative patients displayed in (A). (C) In the dot plot, means ± SEM of the OD values of HS1-Y397 phosphorylation, calculated as in (A), from 40 primary samples divided into 2 groups based on 2DE-detected HS1 status (HS1^hypo-p, HS1^hyper-p), show high HS1-Y397 activation in HS1^hypo-p cells but low HS1 activation in HS1^hyper-p cells (n = 22 HS1^hypo-p vs n = 18 HS1^hyper-p). The numbers in the dot plot refer to the representative samples displayed in (A). (D) In the dot plot, means ± SEM of the OD values of LYN-Y396 phosphorylation, calculated as in (A), from 47 primary samples divided into 2 groups based on 2DE-detected HS1 status (HS1^hypo-p, HS1^hyper-p), show high LYN-Y396 activation in HS1^hypo-p cells but low LYN activation in HS1^hyper-p cells (n = 27 HS1^hypo-p vs n = 20 HS1^hyper-p). The numbers in the dot plot refer to the representative samples displayed in (A). *P ≤ .05; ***P ≤ .001, Mann-Whitney U test; ****P < .0001, Spearman rank correlation.